CONTROL DEVICE FOR POWER STEERING DEVICE
There is provided a control device for a power steering device that provides stable steering feeling in the vicinity of a stroke end. The control device for the power steering device is configured to calculate a stopper torque that is a steering force in a direction opposite to a direction causing a turning angle to approach a stopper angle, based on a steering torque signal, when the turning angle approaches the stopper angle accompanied with a steering operation of a steering wheel, and configured to calculate a motor command signal that is used to drive a power-driven motor, based on a driving condition of a vehicle and the stopper torque.
1 . A control device for a power steering device including a steering mechanism configured to steer a turning wheel accompanied with a steering operation of a steering wheel and a power-driven motor configured to apply a steering force to the steering mechanism, the control device for the power steering device comprising;
a turning angle signal receiving portion configured to receive a turning angle signal that is a signal indicating a turning angle of the turning wheel;
a steering torque signal receiving portion configured to receive a steering torque signal that is a signal indicating a steering torque of the steering mechanism;
a stopper angle setting portion configured to set a stopper angle that is an angle set in a range of the turning angle from a stroke end on one side to a stroke end on an opposite side;
a stopper torque calculating portion configured to calculate a stopper torque that is a steering force in a direction opposite to a direction causing the turning angle to approach the stopper angle when the turning angle approaches the stopper angle accompanied with a steering operation of the steering wheel, based on the steering torque signal; and
a motor command signal calculating portion configured to calculate a motor command signal that is used to drive the power-driven motor, based on a driving condition of a vehicle and the stopper torque.
2 . The control device for the power steering device according to claim 1 ,
wherein the stopper angle setting portion sets a position offset by a predetermined amount from the stroke end on the one side in a direction toward the stroke end on the opposite side, as a stopper angle on the one side, and sets a position offset by a predetermined amount from the stroke end on the opposite side in a direction toward the stroke end on the one side, as a stopper angle on the opposite side.
3 . The control device for the power steering device according to claim 2 ,
wherein the stopper torque calculating portion comprises a gain correcting portion configured to correct the stopper torque with a gain, wherein
the gain is set to increase the stopper torque when the turning angle becomes closer to the stroke end on the one side or closer to the stroke end on the opposite side.
4 . The control device for the power steering device according to claim 3 ,
wherein the gain is set to a value 1 when the turning angle is equal to the stopper angle on the one side or equal to the stopper angle on the opposite side.
5 . The control device for the power steering device according to claim 4 ,
wherein the gain is set to be larger than a value 1 when the turning angle is closer to the stroke end on the one side than the stopper angle on the one side or is closer to the stroke end on the opposite side than the stopper angle on the opposite side.
6 . The control device for the power steering device according to claim 5 ,
wherein the gain is set to increase with approach of the turning angle to the stroke end on the one side, when the turning angle is closer to the stroke end on the one side than the stopper angle on the one side, and
the gain is set to increase with approach of the turning angle to the stroke end on the opposite side, when the turning angle is closer to the stroke end on the opposite side than the stopper angle on the opposite side.
7 . The control device for the power steering device according to claim 2 ,
wherein when the turning angle is closer to the stroke end on the one side than the stopper angle on the one side, the stopper torque calculating portion calculates the stopper torque such that the power-driven motor generates a torque in a direction back toward the stopper angle on the one side, and
when the turning angle is closer to the stroke end on the opposite side than the stopper angle on the opposite side, the stopper torque calculating portion calculates the stopper torque such that the power-driven motor generates a torque in a direction back toward the stopper angle on the opposite side.
8 . The control device for the power steering device according to claim 2 ,
wherein the motor command signal calculating portion does not calculate the motor command signal based on the stopper torque, when speed of the vehicle is equal to or higher than a predetermined vehicle speed.
9 . The control device for the power steering device according to claim 1 , further comprising:
a target turning angle receiving portion configured to receive a signal indicating a target turning angle that is a target angle of the turning angle, wherein
the stopper angle setting portion sets the target turning angle as the stopper angle.
10 . The control device for the power steering device according to claim 9 ,
wherein the stopper torque calculating portion comprises a gain correcting portion configured to correct the stopper torque with a gain, wherein
the gain is set to increase the stopper torque with approach of the turning angle to the stopper angle.